Netflix’s new sci-fi show by Babylon 5 alum J. Michael Straczynski, Sense 8, is all about eight characters around the world who can suddenly communicate with each other telepathically. Suitably, that’s also how Straczynski and company came up with the show’s synthy, trance-like theme song: they took eight random subjects, showed them some looping psychedelic footage, and recorded their brainwave patterns, extrapolating it all into a single Brainwave Symphony.

“There is something musical about the way the brain works,” Straczynski observes. “It’s a symphony on its own terms.”

Working with technologist Patrick Gunderson, the Sense 8 showrunners took eight random subjects, and exposed them to trippy images that were designed to provoke an emotional response. Fitting them with headband sensors, Gunderson and his team then recorded their subjects’ alpha, beta, delta, gamma, and theta waves.

But how were these waves turned into music? Here’s how the official site describes the process:

The Symphony itself was conceived like a jazz chart where the structure of the overall tune is defined and followed, but the individual performances aren’t known until they happen, they’re improvised in the moment. We provided the rhythm section and the song flow, but the individual melody points are taken from our participants’ brainwaves as a form of improvisational performance.

In other words, while the majority of Brainwave Symphony was specifically composed, certain variables in the melody ended up being controlled by the brainwave patterns of the Symphony’s human subjects.

It’s a little bit of a cheat, but the finished composition still has a sort of guttural, id-like musical effect: it does feel like the random throbbing of a psychic gestalt.